Wear-corrosion resistance of aluminum alloy MAO coating by 3D-printing textured PPUA coatings

Micro-arc oxidation (MAO) is a widely utilized surface modification technique for aluminum alloys, but its inherent porosity compromises both wear and corrosion resistance in aggressive environments. This study addresses these limitations by integrating a photocurable polyurethane acrylate (PPUA) coating with different surface textures onto the MAO-treated aluminum alloy using 3D printing. Mercury intrusion porosimetry revealed that the PPUA coating significantly reduced porosity and total intrusion volume, leading to a denser and less permeable surface. Tribological evaluations demonstrated that surface texture plays a critical role in friction and wear behavior. The flat surface exhibited the highest friction coefficient and the highest wear rate. Square textured surface displayed a moderate friction coefficient but suffered from severe plastic deformation and debris accumulation, contributing to an increased wear rate. Meanwhile, circular textured surface exhibited the lowest friction coefficient and wear rate. Potentiodynamic polarization tests confirmed that the PPUA coating significantly enhanced corrosion resistance by increasing the corrosion potential and reducing the corrosion current density, effectively limiting electrolyte infiltration. These findings suggest that the combination of MAO with a tailored photocurable polymer coating offers a promising approach to optimizing the mechanical durability and corrosion protection of aluminum alloys for advanced engineering applications.